


Black Nightshade

by abandonedplant



Category: Dr. STONE (Anime), Dr. STONE (Manga)
Genre: Alpha/Beta/Omega Dynamics, Angst, Discord: The Kingdom of Shipping (Dr. STONE), Fluff, Knotting, M/M, Masturbation, Mutual Pining, Size Difference, TheKingdomofShipping
Language: English
Status: Completed
Published: 2019-11-13
Updated: 2019-11-13
Packaged: 2021-01-29 18:23:54
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 2
Words: 5,106
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/21414634
Author URL: https://archiveofourown.org/users/abandonedplant/pseuds/abandonedplant
Summary: (Manga Spoilers up to Chapter 99, author read up to Chapter 129 before writing fic)First full fic! Dr. Stone made me do it. First chapter is Teen And Up, second chapter is Explicit. A/B/O AU where Gen and Tsukasa get to know each other before humanity is petrified.
Relationships: Asagiri Gen/Shishiou Tsukasa
Comments: 7
Kudos: 64





	1. Chapter 1

**Author's Note:**

  * For [History_Buff](https://archiveofourown.org/users/History_Buff/gifts).

Gen first met Shishiou Tsukasa as another guest on a variety show. They each had a segment where they performed their respective acts, followed by a skit involving all the guests.

Tsukasa was the second-to-last act. Even without saying a word, his calm visage and powerful frame exuded a magnetism that drew all eyes to him, including Gen’s. Gen could attest it was charisma apart from Tsukasa’s inherent Alpha dynamic. He was so tall his head brushed against the tacky, colorful paper streamers decorating the ceiling of the stage arena, where he demonstrated animal-style martial arts against their real-life counterparts. The show technicians strapped sensors to his lean, muscular body. His hands flew out to strike faster than a rattlesnake, and he moved with the grace and agility of a monkey. Gen was pretty sure a few of the more sensitive Omegas in the audience were on the verge of fainting from arousal when Tsukasa ripped the throat out of an anatomical model like a tiger clawing its prey. For his part, Gen made sure he looked just interested enough. It wasn’t hard, actually. He marveled at the physical and mental training it must have taken to develop his muscle memory and propioception to such a high degree.

Gen followed with his current 10-minute routine, ending his act with having the host randomly pick a seat number. Minutes later, a courier arrived with a box postmarked two days ago and addressed to the person in that exact seat. Inside was a fresh bouquet of Gen’s signature flower. Gen motioned the old woman to the stage, so the camera could zoom in to verify the information on the package. He took a moment to appreciate the look of delighted wonder on her face, then picked one of the flowers, smiled, and thanked her for her help.

He idly twirled the stem in his hand on his way to his podium for the skit. Tsukasa was next to him, and Gen offered him the flower with a wink, “You were amazing, Tsukasa-chan.” There, a little flirting with an impressive Alpha every now and then could only help his image. Tsukasa examined the star shaped white petals and prominent yellow stamen. He brought it up to his nose to smell it.

“Ah, you’ll find black nightshade doesn’t really have a scent. It makes it useful for acts requiring discretion. It also means ‘liar’ in the language of flowers. Fitting for a mentalist, wouldn’t you say, Tsukasa-chan?” No need to reveal the absence of scent also suited him perfectly.

“Thank you for the flower, and the lesson.” Tsukasa smiled and tucked the flower behind his right ear. “Your skill was also incredible. I know it all hinges on forcing the host to pick the seat you want him to, but even watching you closely, I couldn’t see _how_ you did it.”

Gen stepped up onto his podium and noted Tsukasa still dwarfed him by around 30cm. “Ah, so there’s more to the Strongest High School Primate MMA fighter than meets the eyes. I’ll have to be extra-careful when you’re in the audience!”

The skit was a quiz show based on common media tropes. The host gave an abbreviation and a definition, and the first person to buzz in with the correct trope would get a point. The other two contestants were Daiki, a comedian, and Reina, a pop singer.

“Alright contestants! First trope: the letters are ‘MC’ and the definition is, ‘A popular romcom sub genre that focuses on ideal scenarios of an Alpha and Omega’s first time bonding.’ Sorry Reina, Daiki beat you to it. What’s the answer?”

“Mate-Cute, of course! Oh man, my favs are when they meet and bond in the same day. They just know, ya know? Also helps if the Omega is allll blushing and shy at first.”

The host waited for the loud applause to subside before continuing. “You are correct, and a man of distinguished taste! The next letters are “RTR” and they stand for a character clawing his way up from poverty to financial success! Gen, you’re first to the buzzer.”

“Rags to Riches, a genre that succeeds in being both aspirational and suffocating. Why beat them when you can join them?”

“Correct! And you could say that both you and Tsukasa have RTR stories to tell. Tsukasa’s family was on the verge of bankruptcy from paying his sister’s medical bills. Gen, you were bullied for being poor and having, what was it, Warden disease?”

“Waardenburg syndrome. Dear audience, you may have noticed the extra space between my blue eyes; this is not an illusion! However, this is…” He waved his hand between his face and the audience, and the hair on the right side of his head turned from black to white. The audience gasped and applauded.

“And now here you are! Proof that with hard work and determination, _anyone_ can be rich and famous! And he’s single, Alphas! Ok, next letters are ‘BBB’ and the definition is ‘Close friend of the protagonist who is usually level-headed and calm, offering sound advice (which the protagonist _usually_ ignores).’ Reina, you go girl!”

“BBB stands for Backing Beta Bestie. They’re usually my favorite characters, to be honest. Like, since Betas don’t bother with sex and romance drama, they’re just these cool operators dishing out the real talk. I mean, everyone should have a BBB. I know that’s not possible, since they’re in the minority, but a girl can dream!”

“That’s right! And now for the next one…” At this point Gen switched to autopilot, giving a few answers with clever quips here and there. His attention was instead focused on Tsukasa, who actually hadn’t answered any. Trying to play dumb? No, he looked genuinely nonplussed at all of the responses. A grueling training regiment must not leave much spare time for movies or shows.

***

He and Tsukasa met again as celebrity judges on the first season of a talent show, and they bonded over their common background and celebrity status. In the green room, they discussed socioeconomics and ribbed each other over the absurdity of their jobs.

Sitting in close proximity over such long stretches in the stale air of the green room, Gen wasn’t surprised that Tsukasa noticed. After all, his friend had spent years finely honing all of his senses.

“You’re a Beta, Gen?”

“Ah, looks like my Omega cologne is no match for your keen nose, Tsukasa-chan!”

“You shouldn’t have to hide.”

“Think of it as practice, Tsukasa-chan.”

“You don’t need it. You’re the best mentalist in the business.”

“Your flattery falls on deaf ears.”

“Fine. I understand. Now let’s go out there and get paid to let people watch us watch people audition to replace us.”

“Only if you promise to debut the catch phrase we created.”

***

“My primate senses only recognize STRENGTH and PURITY! Your performance was a BLACK VOID!”

“Now, now, Tsukasa-chan, I happened to think Hideo-kun’s stand-up routine had a depthless grasp of the plight of today’s youth due to their laziness and sense of entitlement.”

“I ought to punch some sense into you, Mentalist!”

“Waaaah, should I soothe you with a song? Stage Manager, please cut to commercial!”

***

“Hehehe, I totally thought Hideo-kun was going to faint then and there!” Gen draped himself over Tsukasa’s shoulders, watching the replay of the segment from their seats in the green room.

“Hn, maybe denting the table with my fist was a bit much.”

“Noooo! That’s part of your catch phrase now! It’s ‘My primate senses only recognize STRENGTH and PURITY! Your performance was a BLACK VOID! *TABLE SMASH*’ Everywhere you go, you have to carry around a table to smash, should the occasion arise. Like when you’re invited to those posh fundraisers of performative Py-Thro-An-Phil.”

“You’re amazing. You can find the humor in unbearable situations.” Tsukasa’s quiet chuckling subsided, and he turned his head to playfully nuzzle Gen’s hair. “Ah, good, your cologne and the fragrance from your hair dye are fading. I can actually smell _You_.”

Gen felt his face grow warm. “Silly Alpha! You know Betas don’t have any scent to them!”

“Liar.” There was no heat to the insult, just a warm smile that crinkled the corners of Tsukasa’s eyes as they left the studio to grab dinner.

***

Social media and trashy pop news websites picked up on their banter and apparent closeness, and people started to speculate on their relationship. “Ome-ga-bracadabra! Has Asagiri Gen cast a spell on Shishiou Tsukasa?” Gen‘s eyes flitted over the laughably mistaken caption before lingering on the candid photo of him and Tsukasa. They had been exiting the hospital after visiting Tsukasa’s comatose sister. Tsukasa’s handsome face was solemn, and Gen was looking up at him with a small smile. It took a second for him to realize why he hated the post. Intrusion of privacy by paparazzi was a matter of course. As was the intrusive obsession with their personal lives. No, what bothered him was that it reminded him of what he had been thinking in that moment. He loved Tsukasa’s dedication and love for Mirai, doing everything in his power to keep her alive. He loved Tsukasa’s embarrassingly straightforward declarations. He loved bullshitting and chatting and deeply discussing with Tsukasa. He loved Tsukasa. And he wanted to be there for him as more than a friend. Gen hated that he wished the caption were true.

***

“I don’t understand, why are you leaving the show?”

“I need to focus on my next book, that’s all.”

“You wrote your last one while you were on tour.”

“This one is going to require more research.”

“I see. But you’ll keep in touch?”

“Of course, Tsukasa-chan.” It’s the last lie Gen tells him. For the next 3700 years, at least.

***

When Gen broke free of the petrification, he awakened to a Stone World and a stony Tsukasa. He watched helplessly as the man he thought he knew murdered people in cold blood. Or was that stone? He looked on as Senku—an Alpha with starry eyes fixed on unfettered scientific progress—saved Tsukasa figuratively from a blood-soaked utopia and literally from a mortal wound.

After Tsukasa was de-petrified a second time, Gen kept a polite distance. The past was in the past, after all. He was so happy for Tsukasa and Mirai—fully healed from her coma when she was de-petrified—and content to cheer on their little family from afar as he helped rebuild civilization.

“You’re Gen-san, right?” Gen looked up from perusing surveys of the latest group of de-petrified—new citizens of the Kingdom of Science (trademark Senku-chan)—to find Mirai staring him straight in the eye. A spring breeze danced over the courtyard and ruffled her short hair.

“Pleased to meet you, Mirai-chan!”

“Big Brother says you would come with him to visit me in the hospital. I don’t remember, of course, but thanks!”

“You’re very welcome.”

“Can you really do magic?” The expectant look in her eyes telegraphed that right now would be the perfect time for a trick, please and thank you.

“My my! You’ve caught me off guard. Let me just clean up these surveys,” he pushed back his seat and stood up, waving his hands over the desktop. The young girl’s eyes widened in surprise as the writing seemed to vanish from the pages.

“How did you do that?”

“Now now, Mirai-chan, surely Tsukasa-chan told you I’m a liar. You wouldn’t be able to trust any explanation I give you.”

“Do it again! Hold on, let me get my brother!” Mirai dashed off before Gen could protest, dragging back a visibly uncomfortable Tsukasa. Her small hand was wrapped tightly around two of his fingers, not letting him go.

Gen performed the trick again, hyper aware that Tsukasa was looking at his face instead of his hands.

“Can you make my English homework disappear?” And with that she was off again, presumably to the other side of the village to the living quarters to retrieve said homework.

“She’s quite the ball of energy.”

“That she is. It’s like she’s making up for lost time.”

Gen busied himself emptying his overcoat of the actual surveys, putting them in a neat pile next to the blank pages he’d switched them with.

“Why did you disappear on me?” Tsukasa asked softly, a thread of hurt fraying the end. Gen stilled. This wasn’t the time or place for dissembling.

“I’m sorry Tsukasa-chan. I shouldn’t have abandoned you like that. I was frustrated with myself. Scared. I handled it poorly.”

“Scared of me?”

“Scared of telling you how I felt. I’m a Beta after all. I didn’t want to disappoint you. Better to disappear, right?”

“How _do_ you feel about me?” Gen finally looked up and faced Tsukasa. His scars were gone after the second de-petrification, and it shocked him back to that day outside the hospital, afternoon sun filtering through Tsukasa’s long brown hair and illuminating his sadness and resolve.

“I love you and want to be your partner, your mate.” Gen collapsed back into his seat under the weight of Tsukasa’s silence. He kept his head down as he made sure the stack of blank pages was perfectly squared, then thumbed through the surveys to make sure they were still in alphabetical order. “Ridiculous, amirite?” He snapped his fingers and pointed them at Tsukasa, “I stole that line from your future fiancé! I’m kidding. Just trying out my Omega impressions. Not bad for a first try…”

“Thank goodness. I’m so relieved.”

“Huh?”

“I thought you were put off by my advances.”

“What ‘advances?’”

“Asking you out to dinner and escorting you home? Pressing up against you, trying to smell you every chance I could get?”

“I mean sure, that would mean something if I were an Omega…”

“Come off of it. You of all people should know those rigid ideals are mostly regressive stereotypes reinforced by marketing tactics. For a mentalist by trade, you have some huge blind spots.“ Tsukasa reached across the desk to cup the back of Gen’s head, running his fingers through white hair. Gen’s heartbeat quickened as Tsukasa leaned in and inhaled deeply. “You said black nightshade flowers have no scent, but that’s a lie. Spend enough time around them, get to know all about them, and they’re intoxicating. I truly love them.”

Gen closed his eyes, took a deep breath, and turned into Tsukasa’s gentle, passionate kiss. They fumbled a bit, huffing with laughter as they brushed Gen’s hair out and away from their mouths. Tsukasa licked into Gen’s mouth, alternating between tasting him deeply and nibbling at his upper lip. For his part, Gen was fascinated by Tsukasa’s plush lower lip and couldn’t stop running his tongue over it.

Tsukasa wrapped his right arm around Gen’s waist and deftly hauled him up to sit on the desk, scattering the surveys and blank pages everywhere. Gen very much approved of his new position, as it allowed him to pull open Tsukasa’s top and slide his hands along the solid muscles beneath. He felt Tsukasa’s heart beating at a pace to match his own.

“Hey, you _cheated_!” Tsukasa and Gen froze when they heard the crestfallen accusation of a child utterly betrayed. “You just switched the stuff with writing with blank pages!” Gen hopped back to his side of the desk while Mirai was preoccupied with toeing the papers on the ground, her own papers clutched in her hands. “So you can’t make my English homework disappear?”

“Sorry, Mirai-chan, but I can do the next best thing! I’ll help you with your English homework, and afterward I’ll teach you the English version of ‘Part of Your World’ from The Little Mermaid.” As proof, he sang the first verse.

Mirai let out a delighted squeal. “You sound just like Ariel!” She stuck out one hand with her pinky extended. “Pinky promise?”

“Pinky promise!” Gen grabbed her pinky with his own, and they shook on it. Tsukasa shot Gen a grateful and sheepish smile, and Gen mouthed “Later” in return. Then he pulled up a second chair for Mirai, and they dug into her homework. Tsukasa picked up and organized the papers that had been strewn about, then stood behind Gen to watch.


	2. Chapter 2

Over the next few weeks, Gen became a regular visitor at the Shishiou household. He helped Mirai with her English homework and taught her a few simple magic tricks. They usually ate dinner together, and he and Tsukasa discussed the best way to go about fostering an economy of equity and sharing in the Kingdom of Science. Other times they would tell Mirai stories of what happened while she was comatose.

They managed to get together a few times when they had breaks and Mirai was at school. Kissing led to heavy petting led to hand jobs. Gen was sitting in Tsukasa’s lap, lying against his chest. He could just barely circle Tsukasa’s knot with both hands when it was fully engorged. Tsukasa noticed his apprehension.

“We don’t have to ever put it in, you know. Or I can pull out right before it starts to inflate.”

“I know. Plus my body’s not built like an Omega’s. I won’t stretch and get wet to the same extent. It doesn’t help at all that Tsu-chan is huge even by Alpha standards!” Gen mock-scolded him. “Still, we won’t know until we try! Mind over matter! And 99% of a magic trick is preparation. I have a plan to make Tsu-chan’s huge knot disappear into an impossibly small space.” Gen felt Tsukasa’s chest shake with laughter. Tsukasa wrapped his arms around Gen’s waist.

“Ok, Mentalist, what’s your plan?” Gen pulled out a strip of cloth marked off in centimeters and got to work, taking care not to tickle Tsukasa _too_ much.

***

“I’m ten billion percent sure Kaseki knew exactly what he was making. But here you go! The first ‘abstract art glass sculptures’ of the Stone World: Series 1: Lime, Apple, and Grapefruit.” All three had the same shape in three different sizes: a wide base, then a sphere the size of its fruit namesake, then three gradually smaller spheres to create a tapered top. The smallest was light bluish green, the middle one was yellow, and the largest was light purple. “He got to go crazy with colored glass though, so he didn’t ask too many questions.”

“Thank you, Senku-chan!” Gen carefully wrapped the glasswork in cloth and put them in his bag. “Give my regards to Taiju-chan and Yuzuriha-chan!”

“Heh, you can save your thanks and give me a full report on your experience. This will be the first documented Alpha/Beta mating in the Stone World!”

“Eeeh, I’ll talk it over with Tsu-chan. Byeee!”

***

Gen decided to prepare on his own at home. In the evening he came back to his hut from bathing and disrobed. He sat on his sleeping mat, back to the wall and a cushion under his lower back. The candlelight caught on the colored glass. He opened a small jar of goat butter and smeared it on the smallest dildo. He coated the fingers on his right hand with more butter and gently stretched his hole. He spread his knees and imagined Tsukasa’s large palms burning on the inside of his thighs. _Let me see you, Gen._ After a few minutes, Gen reached over for the green dildo. The smallest ball at the tip easily slipped inside, no problem. He worked the other two top balls in as well, then pumped them in and out to get used to the feel and stretch. Every now and then it would bump against his prostate, and the spark of pleasure would make him pump faster. When he felt ready, he applied a little extra pressure. He watched as the lime-sized sphere slowly disappeared inside him and he felt the fullness in his ass. “Whew! That wasn’t so bad!” He left the dildo in place for the moment while he wiped his hands on a washcloth and jotted down his notes. He was still undecided on whether or not he would share them with Senku. Tsukasa said he didn’t mind, and it _would_ help future couples, Betas like him. Maybe they could anonymize the records?

The next one was, of course, harder. Not so much the top part, but his rim protested against the apple-sized sphere. He took deep breaths and focused on the wind in the trees outside. Slowly, slowly the yellow ball was pushed inside. “Eee, that’s a lot!” He wiped the sweat from his brow and took more notes. He’d definitely needed to distract himself and focus on his breathing for this one.

“Ok, time for Papa Bear~” He struggled a bit with the first three balls this time, but the deep breathing and listening to the sounds outside helped. Oh hell, though, it felt like the grapefruit-sized sphere might as well be a watermelon. If he were an Omega, his body would react to his Alpha’s scent and release muscle-relaxing hormones.

I need to relax…maybe coming first would help? He stroked his stiff cock, closing his eyes and imagining Tsukasa’s calloused fingers touching him. He pinched his nipples—Tsukasa biting and sucking on them. He came, his release spurting over his belly and chest.

_”Come on, Mentalist, no napping in the middle of a performance.”_ Gen mimicked his lover’s voice, goading himself to continue. It seemed less impossible, now. He needed better leverage, though. He carefully got on his knees, a little unsteady post-orgasm. He positioned the base of the dildo flush against the bed. As he sat down, the image of a chicken sitting on a large egg flashed in his mind, and he had to tamp down a fit of giggles. He was more relaxed after that, though, and lowered himself down even further. He felt his flesh yield and stretch to the hard glass. Deep breaths, deep breaths.

_”You’re doing so well. Look, it’s almost all the way in.”_ Gen’s knees gave out and he sank the rest of the way down, his hole stretching around the widest part, then closing and sucking the huge sphere all the way inside. So full…imagining it was Tsukasa’s knot instead was almost enough to get him hard again. He was ready.

***

“Thank you for watching Mirai tonight, Yuzuriha.” After school, Gen and Tsukasa had walked Mirai over to the hut Yuzuriha, Taiju, and Senku shared.

“Of course, Tsukasa! We’re going to have lots of fun making seashell necklaces and telling stories, aren’t we, Mirai?”

“Yeah! I’ll sing you the song Big Brother Gen taught me!”

“Don’t skimp on the details in your report, Tsukasa. Remember, the sex lives of future Alpha/Beta pairs are depending on you.”

“Senku!” Yuzuriha clapped her hands over Mirai’s ears. Senku was unfazed by the reprimand and casually picked at his ear.

“Don’t mind him, and we’ll take good care of Mirai!” Taiju clapped Tsukasa on the back. If anyone could keep Senku in check, it was his two Omega mates.

Once they were inside Tsukasa’s hut, the larger man bent down to kiss Gen. He pushed Gen’s overcoat off his shoulders and untied his sash, while Gen unraveled the cloth strip around Tsukasa’s waist. They finished stripping each other and collapsed on the bedding with Gen on his back and Tsukasa crouched between his spread legs. Tsukasa nuzzled at the inside of Gen’s right thigh, his long hair tickling Gen’s left thigh. Gen’s giggling was interrupted by Tsukasa licking a long stripe up his erection. He gently suckled on Gen’s sac, gathering up the clear precome with his right hand and smelling it before reaching up and smearing it on Gen’s nipples. He moved on to nuzzling and licking Gen’s cock while he slid his fingertips over Gen’s nipples, gently pinching and twisting, rubbing the precome into them. He looked up when Gen grabbed onto his hand and watched transfixed as Gen lapped at the tips of his middle and index fingers, then sucked them into his mouth down to the base.

When he released them, Tsukasa brought them down to circle Gen’s hole and made to push them inside.

“Ah ah ah! Tsu-chan! Just one at first, and go slow.”

“Oops, sorry.” Tsukasa gently circled with his index finger, inserting it when the ring loosened up a bit. He took it out and replaced it with his middle finger. He gently introduced the tip of his index finger alongside it. When both were inside Gen, he slowly spread them. He kept suckling on Gen’s erection, pressing his tongue against the underside and swirling it around the tip, watching for when Gen’s eyebrows furrowed in pleasure.

“Mmm, gimme another finger.” Gen felt Tsukasa add his ring finger and stroke his insides. He jolted when Tsukasa softly prodded the bulge of his prostate. Tsukasa built up a rhythm, sucking while his fingertips circled and brushed over the sensitive gland. He looked up questioningly, and Gen gave a slight nod, not trusting his voice. Tsukasa fit his little finger in alongside the others.

Gen buried his hands in Tsukasa’s hair, massaging his scalp and guiding him forward and back, whimpering from the stimulation.

“I’m close, Tsu-chan.” One more lick to the head of his cock and press on his gland, and Gen’s body curled in over Tsukasa’s head as he orgasmed. Tsukasa hungrily drank down Gen’s release, giving tender licks to his spent cock. His fingers still buried inside Gen, he nuzzled up Gen’s belly, inhaling the scent of his sweat-drenched body.

“Hey there.” A brilliant smile spread across his face as he looked Gen in the eyes.

“Hi, Tsu-chan.” Gen leaned up for a kiss, and Tsukasa pressed an ironically chaste kiss to his lips.

With his free hand, Tsukasa brushed Gen’s white hair behind his ear. He kissed his forehead, the scar on his cheek, his collarbones, “You’re beautiful, Gen.”

Gen let himself bask for a few moments before saying, “I’m ready.”

Tsukasa almost reluctantly paused in his ministrations and hitched himself up, withdrawing his fingers from Gen’s stretched hole. Gen pushed down the mild spike of panic induced by instinctual self-preservation at the sight of Tsukasa’s long, thick erection. Gen wrapped his legs around Tsukasa’s waist and dug his heels into his lower back. Tsukasa retrieved the jar of butter from the floor beside the bed and covered himself from base to tip. He locked eyes with Gen and pressed inside. All of the preparation had worked, and Gen felt his insides stretch to accommodate Tsukasa. The head brushed against Gen’s prostate on the way in, and Gen felt his own cock twitch.

“Are you ok?” Tsukasa was fully seated, and Gen could feel the heat of his sac pressed firmly against his ass.

“Tic-Cet-A-Cop, Tsu-chan. Giddy-up. Whoa!” Tsukasa planted his left hand above Gen’s head and wrapped his right hand around Gen’s waist. He pulled away and surged forward, thrusting in and out. He’d been joking, but Gen was left breathless by the raw, animalistic power of Tsukasa’s fucking. That combined with the occasional strokes against his prostate left him hard with his second erection. He reached down and began stroking his cock in time with Tsukasa’s thrusts. “I wish you could see yourself, Tsu-chan. You’re the beautiful one. Wild with love. And you’re looking at me. Remember our talk? I still want it. Do it. Fill me up. Give me your knot. Mark me. It’s not meaningless if we give it meaning.” Tsukasa looked like he was on the verge of tears. He sat back on his haunches, wrapping his arms around Gen’s back and bringing him to sit in this lap. He continued thrusting, raising and lowering Gen’s body as if he weighed nothing. The change in position shifted the way Tsukasa’s cock rubbed against Gen’s prostate, and his erection rubbed against Tsukasa’s abs. Gen cried out as he came, and he felt his release spill over their stomachs. A few thrusts later, Tsukasa stilled, and Gen felt the warmth of his release flood inside him. Then he felt the knot start to swell. He started his deep breathing. Lime, ok no problem, easy-peasy. Apple, he focused on the feeling of Tsukasa stroking his back and nuzzling his neck. The steady rise and fall of his chest.

“You’re doing so well.” This time it was really Tsukasa saying it. “This. Us. It feels so good. I’m so happy it’s you. My Black Nightshade. My Gen. My partner. My mate. I love you.” Gen was so focused on Tsukasa’s words that he didn’t even realize the knot was fully inflated until he felt Tsukasa’s sharp fangs pierce right below his left ear, where an Omega’s scent gland would be. Tsukasa guided Gen’s mouth to the corresponding spot on his neck, and Gen bit down. Tsukasa tilted Gen’s chin up, and they kissed, mingling their blood as they pressed closer together.

***

“Congratulations, you two!” Taiju was the first to notice their marks when they went to pick up Mirai the next morning.

“Congratulations on what?” Mirai ran up, a seashell necklace around her neck and a dozen more hanging from her forearm.

“Gen and Tsukasa got married!” Yuzuriha jumped in to save the situation. Gen would be eternally grateful.

“No fair! I missed the ceremony!”

“Ah, Mirai-chan, we didn’t have one.”

“But Big Brother Gen, you hafta have a ceremony! To have fun and cake!”

“She has a point. We’re due for a summer celebration. The first-ever wedding in the Kingdom of Science!”

“You just want an excuse to try out those fireworks you’ve been developing, don’t you, Senku-chan.”

“Please let me make the garments! And the decorations!”

“Maybe we can get Francois to make the cake. We have a ton of freshly ground flour from our latest harvest.”

“Aaah, I feel like this has gotten away from the couple in question.” Gen was still a little reluctant to show off their status. Committing to each other was one thing. What would people think of a Beta snagging one of the Stone World’s most eligible Alphas, then bragging about it? He could already feel Minami glaring daggers through her camera’s viewfinder.

“Gen, I want to celebrate our union. And I want to show off my Beautiful, Brilliant, Beta partner. All of the people with sense will be happy for us, and the ones who aren’t, aren’t worth considering.”

Tsukasa pulled Gen’s hand up to his face and gazed intently at him, pressing a kiss to his knuckles.

“Oh, all right. But if anyone crashes the wedding, you’d better be ready with your catch phrase.”

“Deal.”

**Author's Note:**

> —In the original Japanese, Gen has a speaking tic where he says words backwards. This works for Japanese, where words are made up of syllables. In the Frankenstein’s monster that is English, I’ve decided to go with having him break up a multisyllabic word (ones with Latin roots work well) and say each syllable in reverse order. So philanthropy becomes Py-Thro-An-Phil.  
—Fight Lab: Man vs Beast: <https://youtu.be/mSIr0F-qXEQ>  
—Thanks to Admin-sama for the headcanon that Gen has Waardenburg Syndrome! <https://ghr.nlm.nih.gov/condition/waardenburg-syndrome>  
—Elements of Color in Stained and Colored Glass: <https://geology.com/articles/color-in-glass.shtml>  
—hPL, Relaxin, and Oxytocin: <https://www.whattoexpect.com/pregnancy/pregnancy-health/pregnancy-hormones/hpl.aspx>
> 
> Feel free to join the Dr. Stone shipping server! All ships are welcome!  
[Click here!](https://discord.gg/dvvtAJN)


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